Composite joist floor system

ABSTRACT

Embodiments of the present invention provide systems for connecting a flooring system to a vertical wall. In one embodiment the building structure includes a floor comprising a cementitious slab and a wall supporting at least a portion of the cementitious slab. A plurality of stand-off fasteners extend from the top of the wall into the cementitious slab and are configured to transfer forces between the cementitious slab and the wall. The stand-off fasteners comprise a lower portion and an upper stand-off portion. The lower portion is operatively coupled to the top of the wall, and the upper stand-off portion extends above the top of the wall and is encapsulated within the cementitious slab. In some embodiments, at least a portion of the lower portion is heat treated to a higher degree of hardness relative to the remainder of the stand-off screw.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of, and claims priority to,co-pending U.S. patent application Ser. No. 14/487,403, filed on Sep.16, 2014 and entitled “COMPOSTE JOIST FLOOR SYSTEM,” which is acontinuation of U.S. patent application Ser. No. 13/862,073, filed onApr. 12, 2013 and entitled “COMPOSTE JOIST FLOOR SYSTEM” which hasissued into U.S. Pat. No. 8,950,143, which is a continuation of U.S.patent application Ser. No. 13/538,491, filed on Jun. 29, 2012 andentitled “COMPOSITE JOIST FLOOR SYSTEM,” now abandoned, which is acontinuation of U.S. patent application Ser. No. 12/019,329, filed onJan. 24, 2008, and entitled “COMPOSITE JOIST FLOOR SYSTEM” which hasissued into U.S. Pat. No. 8,230,657, the entire contents of eachapplication and/or patent are incorporated by reference herein.

FIELD

This invention relates to the field of structural systems for buildings.More particularly, embodiments of the invention relate to improvedcomposite joist floor systems.

BACKGROUND

Large scale, multi-story buildings are typically constructed of steeland concrete. Floors in such buildings may be constructed by spanningwide flange beams or steel joists between structural supports andinstalling metal decking across the tops of such beams or joists. Thedecking forms a horizontal surface onto which concrete is placed.Generally, the bottoms of the beams or joists form the framework fromwhich ceilings are hung. The composite construction is typicallyachieved by using welded shear studs or partial extension of the joisttop chord above the form or metal deck into the concrete slab. Flooringsystem designs must also be mindful of fire safety, acoustics, andvibration considerations.

While joist and deck floor systems have been designed in the past toaddress one or more of these issues individually, these prior designsare not optimized and integrated with the portions of the supportstructure of a building to provide an integrated design to address theabove mentioned issues in a systematic manner.

BRIEF SUMMARY

Embodiments of the present invention address the above needs and/orachieve other advantages by providing an improved and integratedcomposite joist floor system. One aspect of the improved composite joistfloor system includes joists having ends supported by varying supportingmembers. Corrugated steel decking is positioned over the joists suchthat the corrugations are substantially perpendicular to the joists.Self-drilling, self-tapping, stand-off screws are spaced along thelength of the joist, aligned with the deck corrugations. These stand-offscrews provide the required shear transfer between the joist andconcrete slab to form a composite floor system. The placed concreteencapsulates the upper non-threaded shank portions of the self-drilling,self-tapping, stand-off screws and the end of the joists.

After the concrete has cured, the resultant system comprised of steeljoists, steel decking, stand-off screws, and concrete, act together toform a composite system with greater load carrying capacity and lessvertical deflection than a non-composite floor system. Theself-drilling, self-tapping stand-off screws connect the joist upperchords to the concrete slab allowing the joist and concrete slab to actas a unit, by transferring shear between the two joined components. Theconcrete slab then effectively behaves as the upper chord of thecomposite system with a much larger load carrying capacity than thejoist upper chord alone.

To provide additional continuity, fire protection, and stiffness atjoist ends and at slab edge locations, a combination of z-shapedclosures and/or pour stops provide forming for the concrete. A z-shapedclosure is provided having a vertical face, an upper horizontal flange,and a lower horizontal flange. The upper horizontal flange extends overa portion of the corrugated steel decking and the lower horizontalflange is supported by the steel joist supporting member. The verticalface extends between the upper and lower horizontal flanges and has acutout so that at least a portion of the joist end passes through thevertical face. At exterior conditions, break formed pour stops aresupplied. Concrete is then placed over the corrugated steel decking andinto a channel formed at least partially by the z-shaped closure and/orthe pour stop.

In one embodiment, the stand-off screw comprises a first threadedportion having first and second ends and a first helical thread. Thestand-off screw may also include a stand-off portion extending from thesecond end of the first threaded portion, the stand-off portion having afirst end and a second end. The first end of the stand-off portion isproximate to the second end of the first threaded portion. The stand-offscrew may further include a driving section located proximate to thesecond end of the stand-off portion. The driving section is configuredto allow engagement between the stand-off screw and a tool for rotatingthe stand-off screw so that the first threaded portion of the stand-offscrew can be drilled into a support member of the building structure.The stand-off screw may also include a second threaded portioncomprising a second helical thread. The second threaded portion isgenerally located proximate to the second end of the stand-off portionand configured to be used to couple the stand-off screw to an extensionmember.

In general, the decking of the composite floor system comprisescorrugated steel decking where the corrugations of the corrugated steeldecking define a plurality of peaks and valleys. In some embodiments,the stand-off fasteners are located in the valleys of the corrugatedsteel decking, and adjacent stand-off fasteners along a joist areseparated by at least one valley that does not have a stand-off fastenerlocated therein on that joist. In other embodiments, at least twoadjacent stand-off fasteners are located in the same valley of thecorrugated steel decking on that joist.

In some embodiments of the composite floor system, the joist may includea wood member and the lower portion of each stand-off fastener maycomprise a wood screw portion having a helical wood screw thread fordrilling into the wood member. In some embodiments, the decking haspre-formed holes for installing the stand-off fasteners therethrough.

A welded wire fabric may also be located over the decking andencapsulated within the cementitious slab. In some embodiments, any32-inch span of the corrugated steel decking over a joist has betweenthree and nine stand-off fasteners located therein.

In some embodiments, the supporting member that supports the joist iscomprised of a metal stud, a wood stud, a masonry wall, a concrete wall,a metal beam, or a metal truss that extends generally perpendicular tothe joist. A self-drilling, self-tapping stand-off fastener may, inaccordance with one embodiment of the present invention, be drilled intothe end of the joist's upper chord above the supporting member andbeyond the end of the corrugated steel decking.

The joist of the composite floor system may comprise an open web whichmay be comprised of one or more rods having a generally circularcross-section. For example, the web may include a rod bent into agenerally zigzag or sinusoidal pattern such that the rod extends fromone chord to the other chord and then back again.

In some instances, the composite floor system may include a self-tappingscrew drilled through the generally horizontal upper flange of thez-shaped closure into a peak of the corrugated steel decking. Thecomposite floor system may also include a self-tapping screw drilledthrough the generally horizontal lower flange of the z-shaped closureinto the supporting member or a distribution track or other distributionmember positioned between the lower flange and the supporting member.

In some embodiments, the joist's upper chord, lower chord, and shoe areeach comprised of a pair of angles. For example, the upper chord, lowerchord, and shoe may be each made up of a pair of angles spaced apart byrod-shaped members of the web and/or by a rod-shaped end diagonalmember.

The composite floor system may further comprise a pour stop having agenerally horizontal flange and a generally vertical face. Thehorizontal flange of the floor stop is generally positioned adjacent tothe top of the supporting member and the vertical face generally extendsvertically opposite the vertical face of the z-shaped closure. In thisway, the pour stop forms at least a portion of the boundary of thecementitious channel formed over the supporting member. In someembodiments, the pour stop further comprises a lip extending from thetop of the vertical face diagonally toward the corrugated steel decking,the lip being substantially encapsulated within the cementitiousmaterial.

The features, functions, and advantages that have been discussed may beachieved independently in various embodiments of the present inventionor may be combined in yet other embodiments, further details of whichcan be seen with reference to the following description and drawings butare not limited to only these applications shown.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Having thus described embodiments of the invention in general terms,reference will now be made to the accompanying drawings, which are notnecessarily drawn to scale, and wherein:

FIG. 1 illustrates a cross-sectional perspective view of a compositejoist floor system in accordance with an embodiment of the presentinvention;

FIGS. 2a and 2b illustrate a cross-sectional side views of two compositejoist floor systems similar to the floor system illustrated in FIG. 1,in accordance with embodiments of the present invention;

FIG. 3a-d illustrates at least a portion of the z-shaped closureillustrated in FIGS. 1 and 2 in accordance with an embodiment of thepresent invention;

FIG. 4a illustrates a side view of one of the self-drilling,self-tapping, stand-off screws illustrated in FIGS. 1 and 2 inaccordance with an embodiment of the present invention;

FIG. 4b illustrates a cross-sectional side view of the self-drilling,self-tapping, stand-off screw illustrated in FIG. 4a , in accordancewith an embodiment of the present invention;

FIG. 5a-d illustrates the exemplary standardized patterns of stand-offscrew spacings that may be used in accordance with embodiments of thepresent invention;

FIG. 6 illustrates a cross-sectional perspective view of a compositejoist floor system in accordance with an embodiment of the presentinvention where the member for supporting the end of the joists includesa structural steel beam;

FIG. 7 illustrates a cross-sectional perspective view of a compositejoist floor system in accordance with an embodiment of the presentinvention where the member for supporting the end of the joists includesa masonry wall, such as a wall comprised of concrete masonry units orbrick;

FIG. 8 illustrates a cross-sectional perspective view of a compositejoist floor system in accordance with an embodiment of the presentinvention where the supporting member for supporting the end of thejoists includes a concrete wall;

FIG. 9 illustrates a cross-sectional perspective view of a compositejoist floor system in accordance with an embodiment of the presentinvention where the supporting member for supporting the end of thejoists includes a wood stud;

FIG. 10 illustrates a cross-sectional side view of a composite joistfloor system showing how a beam running substantially perpendicular tothe joists may support the ends of two joists on opposite sides of thebeam in accordance with an embodiment of the present invention;

FIG. 11 illustrates a cross-sectional side view of a composite joistfloor system showing how the corrugated steel decking may be supportedat its edge by a wall that runs substantially parallel to the joists andgenerally perpendicular to the corrugations in the decking, inaccordance with an embodiment of the present invention;

FIG. 12a illustrates a cross-sectional side view of a composite joistfloor system where an exterior wall that is substantially parallel tothe joists supports the edges of a corrugated steel decking sheet usinga z-shaped closure, in accordance with an embodiment of the presentinvention;

FIG. 12b illustrates a cross-sectional side view of a composite joistfloor system where an interior demising wall that is substantiallyparallel to the joists supports the edges of two corrugated steeldecking sheets using z-shaped closures, in accordance with an embodimentof the present invention;

FIG. 13 illustrates a cross-sectional view of a composite joist floorsystem where the joist has a flush bearing seat and where the flushbearing seat is supported by a wall running substantially perpendicularto the joist, in accordance with an embodiment of the present invention;

FIG. 14 illustrates another embodiment of a flush bearing seatconfiguration where two opposing joists are supported by the same steelbeam in accordance with an embodiment of the present invention;

FIG. 15 illustrates a flush bearing configuration where the flushbearing seat is configured specifically for a masonry-type supportmember in accordance with an embodiment of the present invention;

FIGS. 16a and 16b illustrate how the composite floor system may beconfigured to transfer horizontal diaphragm shear forces from theconcrete slab to the primary support structures, such as a cold-formedsteel shear-wall, in accordance with an embodiment of the presentinvention;

FIG. 17 illustrates a side section view of a portion of the floor systemat an external wall that is substantially parallel to the floor joistswhere stand-off screws have been installed into the top of the wall totransfer diaphragm forces, in accordance with an embodiment of thepresent invention;

FIG. 18 illustrates an interior support wall in which stand-off screwshave been installed into the top of the wall to transfer diaphragmforces from the concrete slab to the wall in accordance with anembodiment of the present invention;

FIG. 19 illustrates a composite joist floor system where the joists aremade of wood in accordance with an embodiment of the present invention;

FIG. 20 illustrates a side view of the stand-off wood screw illustratedin FIG. 19, in accordance with an embodiment of the present invention;

FIG. 21 illustrates three different exemplary composite joist floorsystems comprising three different cold-formed steel floor joists, inaccordance with embodiments of the present invention;

FIGS. 22a and 22b illustrate a composite floor system supported bycold-formed wall studs, the floor system having a composite headerconfiguration in accordance with an embodiment of the present invention;

FIG. 23 illustrates an embodiment of the present invention where rebarin the concrete slab is coupled to a stand-off screw installed into thetop of a supporting wall;

FIG. 24 illustrates a stand-off screw configured to attach to a rebarmember or some other extension member at the end of the screw oppositethe screw's tip, in accordance with an embodiment of the presentinvention;

FIG. 25 illustrates a stand-off screw used to attach a joist shoe to thesupporting wall in accordance with an embodiment of the presentinvention;

FIG. 26 illustrates how stand-off screws may be used to attach az-shaped closure and a pour stop to a wall, while also functioning tocouple rebar to the wall and/or to transfer horizontal diaphragm forcesfrom the slab to the wall, in accordance with an embodiment of thepresent invention;

FIGS. 27a and 27b illustrate a composite joist floor system configuredto provide for a balcony that extends from the structure parallel to thefloor joists in accordance with an embodiment of the present invention;

FIGS. 28a and 28b illustrate a composite joist floor system configuredto provide for a balcony that extends from the structure perpendicularto the floor joists in accordance with an embodiment of the presentinvention;

FIG. 29 illustrates an exterior slab edge condition within a compositejoist floor system where the concrete floor ends at a joist inaccordance with an embodiment of the present invention;

FIG. 30 illustrates a composite joist floor system where the floorsystem transitions from a deck system, such as that used in a corridor,to a composite joist and deck system in accordance with an embodiment ofthe present invention;

FIG. 31 illustrates a composite joist floor system having a corridorrunning perpendicular to the joists and having a mechanical header, inaccordance with an embodiment of the present invention; and

FIG. 32-32 b provides a more detailed illustration of the mechanicalheader illustrated in FIG. 31, in accordance with an exemplaryembodiment of the present invention.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

Embodiments of the present invention now will be described more fullyhereinafter with reference to the accompanying drawings, in which some,but not all, embodiments of the invention are shown. Indeed, theinvention may be embodied in many different forms and should not beconstrued as limited to the embodiments set forth herein; rather, theseembodiments are provided so that this disclosure will satisfy applicablelegal requirements. Like numbers refer to like elements throughout.

Composite Joist Floor Systems

The composite joist floor systems described herein are generallyconstructed at the building site and make-up the floors and providestructural support for the ceilings of the building. In general, aplurality of joists are provided and each joist is supported at eitherend by the building's primary support structures, which may include butare not limited to: beams, joist girders, masonry walls, concrete walls,cold-formed wall studs, and/or wood load bearing wall studs. In thisway, the joists span the open areas within the building's main structureto provide support for the floors and/or ceilings. Importantly, thepresent invention provides a plurality of varying flooring systemdesigns and design methodologies. These various designs and designmethodologies use a combination of joist depth, chord size, joistspacing, flexible self-tapping stand-off screw size and spacing, andvarious corrugated steel deck profiles to create flooring systems thatare light in weight, have generally decreased material cost andconstruction costs, and offer improved strength.

Typical steel joists of the composite joist systems described hereinhave spans ranging from eight (8) to fifty (50) feet and depths rangingfrom eight (8) to fifty (50) inches. In addition to variations in thesize and spacing of the joist, the number and pattern of the flexibleself-drilling, self-tapping stand-off screws, the configuration of thecorrugated steel decking, the connections between the flooring systemand the support beam, as well as other design elements contribute tolighter weight and added strength of the flooring systems.

Referring to the drawings, FIGS. 1 and 2 illustrate a cross-sectionalperspective view and a cross-sectional side view, respectively, of acomposite joist floor system 1 in accordance with an embodiment of thepresent invention. As illustrated in FIGS. 1 and 2, and as describedabove, the composite joist floor system 1 generally includes at leastone joist 10 supported on its ends by a stud or beam, such as a steelwall stud 60. The joist 10, in combination with other joists, walls, orbeams (not shown), supports a layer of corrugated steel decking 20. Thecorrugated steel decking 20 is positioned such that the corrugations runperpendicular to the joist 10. Importantly, a plurality ofself-drilling, self-tapping stand-off screws 30 are drilled through thecorrugated steel decking 20 into the joist 10. Each self-drilling,self-tapping stand-off screw 30 not only connects the corrugated decking20 to the joist 10, but also extends some distance above the corrugateddecking 20. In this way, when concrete 40 is placed over the corrugatedsteel decking 20, the self-drilling, self-tapping stand-off screws 30are encapsulated within the concrete to form a composite joist floorsystem once the concrete is cured. As will be described in greaterdetail below, this composite joist floor system allows for structures tobe stronger, lighter, and/or more economical. Although the term“concrete” is often used herein when describing embodiments of thepresent invention, other embodiments of the present invention may useother cementitious materials or materials with properties similar tocementitious materials.

As illustrated in FIGS. 1 and 2, in an exemplary embodiment, the joist10 comprises an upper chord 12 and a lower chord 15. The upper chord 12and the lower chord 15 are joined together by a web 18 extendingtherebetween. In the illustrated embodiment, the web 18 has an open webconfiguration comprised of one or more of rod, angle, or cold-formed “C”shaped members 19 that extend between and are coupled to the upper chord12 and the lower chord 15. In the illustrated embodiment of theinvention, the web 18 is made primarily from a single round solid rod 19bent into a zigzag or sinusoidal-like pattern having one or more peaksalternating with one more valleys. In such an embodiment, the upperchord 12 is welded (or otherwise coupled) to the peaks in the bent rod19 and the lower chord 15 is welded (or otherwise coupled) to thevalleys in the bent rod 19.

In the illustrated embodiment, the upper and lower chords 12 and 15 areeach formed from two metal angles (also sometimes referred to as “angleirons,” although the angles described herein need not be iron). FIG. 1illustrates an embodiment where two angles 16 and 17 are placed oneither side of the bent rod 19 and joined to the valleys in the bent rod19 to form the lower chord 15. Similarly, two angles 13 and 14 areplaced on either side of the bent rod 19 and joined to the peaks in thebent rod 19 to form the upper chord 12. So that the composite joistfloor system 1 is relatively light in weight, the upper chord 12 and thelower chord 15 typically have relatively thin cross sections.

As further illustrated in FIGS. 1 and 2, the joist 10 includes arod-shaped “end diagonal” 25 at each end of the joist for transferringforces between the joist 10 and the wall stud 60. The “end diagonal” 25may also potentially consist of angles or cold-formed “C”-shapedsections for heavier floor loadings. One end of the end diagonal 25 isjoined to the lower chord 15 proximate to the first web joint and theother end of the end diagonal 25 is joined to the upper chord 12proximate to the seat or joist shoe 70. In some embodiments, the lowerchord 15 of the joist 10 may include a ceiling extension 90 that extendsthe lower chord 15 such that the lower chord 15 ends proximate to thesupporting wall 60 or beam, as the case may be. Such an extension may bedesired so that a ceiling 100 may be hung from the lower chord 15 of thejoist.

As described above, corrugated steel decking 20 is positioned over thejoist 10 and generally spans two or more adjacent joists. The corrugatedsteel decking 20 may be painted or galvanized. Standard corrugated steeldecking generally comes in the form of sheets having for example,coverage widths of 32, 33, or 36 inches. Besides coming in a variety ofwidths, standardized corrugated steel decking also comes in manydifferent profiles, depending on the application. The type of corrugatedsteel decking primarily illustrated herein is 1.0 deep steel decking,although other types of decking may be used depending upon theapplication. In one embodiment, the steel used in the decking is madefrom approximately 70% recycled materials and the steel used in thejoists is made from approximately 99% recycled materials.

As illustrated in FIGS. 1 and 2, the corrugated steel decking 20 isgenerally positioned such that the corrugations run at right angles tothe joist 10. As described above, self-drilling, self-tapping stand-offscrews 30 are drilled through the corrugated decking 20 and the flangesof the upper chord 12. In this way, the self-drilling, self-tappingstand-off screws 30 transfer compressive forces from the joist top chordinto the concrete slab 40 of the joist 10. The concrete floor slab 40 isdesigned with sufficient compressive strength to resist thesecompressive forces.

In some embodiments, the concrete is strengthened by placing welded wirefabric 45 or other types of rebar over the corrugated steel decking 20.When the concrete 40 is then placed over the welded wire fabric 45 andthe corrugated steel decking 20, the welded wire fabric 45 and the upperportion of the self-drilling, self-tapping stand-off screws 30 areencapsulated within the concrete 40. The concrete is then smoothed so asto form a floor of the building. In some embodiments, chairs are used tohold the welded wire fabric 45 in the specified location above thecorrugated steel decking 20 as the concrete 40 is placed.

It should be appreciated that the composite joist floor system 1described above provides many advantages over the traditionalnon-composite floor systems. In a traditional non-composite floordesign, the concrete slab rests on the joist and the concrete slab andthe joist act independently to resist the loads on the floor.Specifically, in a non-composite joist floor design, the joist and theconcrete share the loads based on the relative stiffness of eachcomponent. Since the concrete slab is relatively thin compared to itsspan (i.e., the length of the joist), the concrete has very lowstiffness relative to the joist. As such, in a non-composite joist floordesign, the joist must carry substantially the entire load on the floor.In contrast, in the composite joist floor system described above, theconcrete slab 40 and the joist 10 act more like a single unit due to thefact that the concrete slab 40 and the joist 10 are coupled together bythe stand-off screws 30. In general, the concrete 40 carries compressionand the lower chord 15 of the joist 10 carries tension. As such, thedesign moment is based on the concrete strength, the steel strength, andthe shear transfer between the two. The self-drilling, self-tappingstand-off screws 30 function as a shear transfer mechanism. Since theconcrete 40 carries much of the compressive stresses that wouldotherwise have to be carried by the upper chord of the joist in anon-composite joist floor system, a composite joist floor system allowsthe upper chord 12 to be reduced in size and weight. In this way, thematerial used in the structure can be reduced to reduce weight andcosts. Alternatively, the material that would otherwise have been usedin the upper chord 12 can be transitioned to increase the size andstrength of the lower chord 15 to achieve significant increases in loadcapacity without an increase in material. Therefore, in some embodimentsof the present invention, the upper chord 12 of the joist 10 is smallerthan the lower chord 15 or is formed from of lower strength materialcompared to the material used to form the lower chord 15.

Returning to FIGS. 1 and 2, as described above the end of the joist 10is supported by a beam, wall, stud, or other structural member. In theillustrated example, the end of the joist 10 is supported by a steelwall stud 60. The end of the upper chord 12 has a shoe 70 fortransferring forces from the joist 10 to the wall stud 60. In theillustrated embodiment, the shoe 70 is made up of a pair of metal angleswelded to the bottoms of the upper chord's angles 13 and 14. Configuredas such, the angles 13 and 14 that make up the upper chord 12 and theangles 71 and 72 that make up the joist shoe 70 combine to form anI-beam like bearing connection. The end of the end diagonal 25 ispositioned between the shoe angles 71 and 72 and serves as a spacerbetween the shoe angles. In this regard, the shoe angles 71 and 72 arewelded to the end diagonal 25 in addition to being welded to the upperchord angles 13 and 14.

The bottom surface of the joist shoe 70 rests upon the top surface ofthe wall 60. As illustrated in FIG. 2a , a distribution member 65 orheader and/or a distribution track 62 or plate may be positioned betweenthe top of the wall studs and the bottom of the joist shoe 70 todistribute force along the length of the wall 60. In other embodiments,as illustrated in FIGS. 1 and 2 b, only a distribution plate 62 is used.

As further illustrated in FIGS. 1 and 2, in some embodiments of thecomposite joist floor system 1, the corrugated steel decking 20 does notextend significantly over the wall stud 60 or other supporting member.In this way, when the concrete 40 is placed over the steel decking 20,the concrete 40 may flow or be placed into the region 41 above thesupporting wall 60. The concrete 40 in this region 41 encapsulates theends of the upper chords 12 of each joist 10 and the ends of each joistshoe 70 and functions to help hold the joist shoes 70 in place at thetop of the wall 60. The concrete 40 in the region 41 also forms aconcrete beam extending over the wall 60 perpendicular to the joists 10.This concrete beam helps to collect and distribute forces beingtransferred between the walls and the floor. As illustrated in FIGS. 1and 2, a z-shaped closure 50 and a pour stop 55 are used to contain theconcrete 40 within the region 41 over the upper end of the wall 60. Inaddition to the structural benefits of a floor system having such aconcrete beam, floor systems that allow the concrete 40 to contact theupper end of the wall 60, such as the floor systems illustrated in FIGS.1 and 2, typically lead to improved fire-safety ratings and improvedacoustic attenuation.

In the embodiment illustrated in FIG. 2a , a pour stop 55 is used toprevent the concrete 40 from flowing beyond the plane of the supportingwall 60 as the concrete 40 is curing. The pour stop 55 has a lowerhorizontal flange 58 and a vertical face 57. The horizontal flange 58rests atop the distribution member 65 and may be coupled to thedistribution member 65 by, for example, a self-tapping screw 56. Thepour stop 55 is positioned such that the vertical face 57 issubstantially within the same plane of the backside of the wall 60 sothat the vertical face 57 of the pour stop 55 prevents the concrete fromflowing beyond this plane. In a preferred embodiment, the pour stop 55has a lip 59 at the top of the vertical face 57 that curves or isotherwise bent inward and downward toward the joist 10. The lip 59prevents the vertical face 57 of the pour stop 55 from becomingseparated from the concrete slab 40 and, therefore, prevents moisturefrom entering between the pour stop's vertical face 57 and the concrete40. In other embodiments, the pour stop 55 may not include the lip 59.In one exemplary embodiment, the height of the pour stop 55 is sizedsuch that a 2.5 to 3-inch deep 3000 pounds per square inch minimumcompressive strength cast-in place concrete slab is created over the topof the corrugated steel decking 20.

Opposite the pour stop 55, a z-shaped closure 50 is provided. Incombination with the joist 10 and the corrugated steel decking 20, thez-shaped closure 50 functions to contain the concrete 40 within theregion 41 above the wall 60. FIG. 3 illustrates a portion of a z-shapedclosure 50 in accordance with an embodiment of the present invention. Asillustrated in FIG. 3, the z-shaped closure 50 has a generally verticalface 53, a generally horizontal upper flange 52 extending away from thewall 60, and a generally horizontal lower flange 51 extending in adirection opposite from the upper generally horizontal flange 52. In theillustrated embodiment, the vertical face 53 has a cutout 110 at oneend. The cutout 110 has the shape of approximately one-half of anI-beam. This cutout 110 is configured to fit around at least one side ofthe I-beam formed by the combination of the upper chord 12 and the joistshoe 70, as illustrated in FIGS. 1 and 2. As also illustrated in FIGS. 1and 2, the vertical face 53 of the z-shaped closure extends upwardsfurther than the top of the upper chord 12 so that the generallyhorizontal upper flange 52 extends above at least one peak in thecorrugated steel decking 20. Self-tapping screws 54 a and 54 b, welds,pneumatic pins, or a variety of other fasteners may be used to couplethe generally horizontal lower flange 51 to the distribution member 65and the generally horizontal upper flange 52 to a peak in the corrugatedsteel decking 20, respectively.

As illustrated in FIG. 3c , in some embodiments of the invention, thegenerally horizontal lower flange 51 is configured such that, before thez-shaped closure 50 is installed in the floor system 1, it forms anangle with the generally vertical face 53 that is greater than 90degrees. For example, the z-shaped closure illustrated in FIG. 3c formsa 100-degree angle between the generally vertical face 53 and thegenerally horizontal lower flange 51. When such a z-shaped closure 50 isinstalled in the floor system 1, the z-shaped closure 50 may be pressedinto position such that the angle between the generally vertical face 53and the generally horizontal lower flange 51 is reduced to an anglecloser to 90 degrees. When the z-shaped closure 50 is installed in thismanner, the resilient bias of the z-shaped closure 50 will press thehorizontal lower flange 51 against the top of the wall 60 and, thereby,create a better seal between the wall 60 and the z-shaped closure 50than would have otherwise been formed using a z-shaped closuremanufactured to have a 90-degree angle between the generally verticalface 53 and the generally horizontal lower flange 51.

As described above and as illustrated in FIGS. 1 and 2, the compositejoist flooring system 1 includes a plurality of self-drilling,self-tapping stand-off screws 30 screwed through at least some of thevalleys in the corrugated steel decking 20 and through a horizontalflange of the upper chord 12. As further illustrated, a portion of eachself-drilling, self-tapping stand-off screw 30 continues to extendupwards above the corrugated steel decking 20 after the self-drilling,self-tapping stand-off screw 30 is fully installed through the decking20 and the upper chord 12. The stand-off screw 30 has a lower collar 430that functions to secure the corrugated steel decking 20 to the upperchord 12. The upper portion of the self-drilling, self-tapping stand-offscrew that extends above the steel decking 20 becomes encapsulatedwithin the concrete 40. In this way, the self-drilling, self-tappingstand-off screws 30 connect the joist's upper chord 12 to the concreteslab 40 allowing the joist 10 and concrete slab 40 to act as a unit, bytransferring shear between the two joined components. In other words,the stand-off screws 30 cause the concrete slab 40 to function as theupper chord of the composite joist system with a much larger loadcarrying capacity than the joist's upper chord 12 alone. Specifically,tensile forces in the joist lower chord 15 are transferred to horizontalcompressive forces in the concrete slab 40. The high compressivecapacity of the concrete efficiently carries this compressive force.

In order for the self-drilling, self-tapping stand-off screws 30 to moreuniformly transfer the horizontal shear loads along the length of thecomposite steel joist, the stand-off screws 30 are designed so that theyare at least somewhat ductile. As the shank of the stand-off screwsbends, shear load is shared with stand-off screws located more towardthe middle of the joist span. However, in addition to being ductileenough to share the shear loads without breaking, the self-drilling,self-tapping stand-off screw 30 must also have sufficient hardness toallow it to drill through the corrugated steel decking 20 and the upperchord 12 of the joist 10. To accommodate both design requirements, theself-drilling, self-tapping stand-off screw 30 is specially heat treatedso that the lower screw portion of the stand-off screw 30 has sufficienthardness for drilling while the upper portion remains sufficientlyductile.

FIG. 4a illustrates a side view of one of the self-drilling,self-tapping stand-off screws 30 illustrated in FIGS. 1 and 2 inaccordance with an embodiment of the present invention. Eachself-drilling, self-tapping stand-off screw 30 has an elongated shank417 with an unthreaded shank portion 419 and integral threaded screwportion 418 having helical threads. The unthreaded shank portion 419generally ranges from about two (2) inches to about four-and-a-half(4.5) inches in length depending on the application and the thickness ofthe concrete slab 40. The self-drilling, self-tapping stand-off screw 30has a fluted drill tip 420 projecting from the lower end of the threadedscrew portion 418. Located at the end of the stand-off screw 30 oppositethe drill tip 420 is a driving head 421 configured to engage a drivingtool capable of rotating the stand-off screw 30. An integral flange 426is located between the threaded and unthreaded portions 418 and 419 ofthe stand-off screw 30 forming a lower collar 430 that is used to drawdown the decking 20 during installation and hold the decking 20 firmlyagainst the joist 10.

FIG. 4b illustrates a cross-sectional side view of the self-drilling,self-tapping stand-off screw 30 illustrated in FIG. 4a . The cross hatchpattern in FIG. 4b represents an area of the stand-off screw that isheat treated to a higher degree of hardness relative to the remainder ofthe stand-off screw, in accordance with an embodiment of the presentinvention. As illustrated in FIG. 4b , a lower portion of theself-drilling, self-tapping stand-off screw 30, including the drill tip420 and at least some of the threads 428, is heat treated to a degree ofhardness that enables the stand-off screw 30 to effectively drill andtap into the steel decking 20 and the joist's steel upper chord 12. Inone embodiment, the self-drilling, self-tapping stand-off screws arecomprised of stand-off screws described in U.S. Pat. No. 5,605,423 toMichael Janusz, which is incorporated herein by reference.

In one embodiment, the self-drilling, self-tapping stand-off screws areinstalled in every valley of the corrugated steel decking 20 along thelength of the joist 10 as described, for example, in U.S. Pat. No.5,605,423. However, in a preferred embodiment of the present invention,the self-drilling, self-tapping stand-off screws 30 are only installedas necessary for the particular composite joist floor system and itsapplication. By providing increased spacing between at least some of thestand-off screws 30, such as by installing stand-off screws only inevery other valley of the corrugated steel decking 20, the constructiontimes and costs can be significantly reduced. Furthermore, theattachment patterns may be standardized for particular design scenariosin order to simplify installation of the self-drilling, self-tappingstand-off screws 30. For example, FIG. 5 illustrates an exemplary set ofscrew spacing standards that may be used in embodiments of the presentinvention.

Specifically, FIGS. 5a through 5d illustrate 1.0C-type steel deckinghaving 32-inch wide coverage. FIG. 5a illustrates 32/3 spacing whereeach 32-inch width of corrugated steel decking 20 contains threeself-drilling, self-tapping stand-off screws 30. FIG. 5b illustrates32/4 spacing where each 32-inch width of corrugated steel decking 20contains four self-drilling, self-tapping stand-off screws 30. FIG. 5cillustrates 32/5 spacing where each 32-inch width of corrugated steeldecking 20 contains five self-drilling, self-tapping stand-off screws30. FIG. 5d illustrates 32/6 spacing where each 32-inch width ofcorrugated steel decking 20 contains six self-drilling, self-tappingstand-off screws 30.

As illustrated in FIG. 1, it is generally preferable to drill adjacentself-drilling, self-tapping stand-off screws through the upper chord 12on alternating sides of the web 18. For increased floor capacities, thequantity of self-drilling, self-tapping, stand-off screws may beincreased as shown from FIG. 5a through FIG. 5 d.

FIGS. 6-9 illustrate variations of the embodiment of the composite joistfloor system described above in FIGS. 1-5. More particularly, FIG. 6illustrates a composite joist floor system 600 in accordance with anembodiment of the present invention where the supporting member forsupporting the end of the joist 610 includes a structural steel beam660.

FIG. 7 illustrates a composite joist floor system 700 in accordance withan embodiment of the present invention where the supporting member forsupporting the end of the joist 710 includes a masonry wall 760, such asa concrete block or a brick wall. In such an embodiment, the wall 760may include a concrete-filled channel 765 running through the uppermostblocks or bricks in the wall 760 so that masonry screws may be insertedinto the concrete to hold, for example, the pour stop 755 or the joistshoe 770 in place and so that the forces from the concrete floor slabare more evenly distributed throughout the wall 760. As also illustratedin FIG. 7, the concrete-filled channel 765 may have rebar 762 providedtherein for reinforcing the concrete in the channel.

FIG. 8 illustrates a composite joist floor system 800 in accordance withan embodiment of the present invention where the supporting member forsupporting the end of the joist 810 includes a concrete wall 860. FIG. 9illustrates a composite joist floor system 900 in accordance with anembodiment of the present invention where the supporting member forsupporting the end of the joist 910 includes a wood stud 960. In such anembodiment, two or more wood supporting members 965 may be used todistribute the force from the concrete slab throughout the wall. Asillustrated, all of the floor systems shown in FIGS. 6-9 utilize many ofthe same structures and configurations describe above with reference toFIGS. 1-5.

FIG. 10 illustrates a sectional side view of composite joist floorsystem 1000 showing how a beam 1065 running substantially perpendicularto the joists may support the ends of two joists 1010 a and 1010 b onopposite sides of the beam 1065 in accordance with an embodiment of thepresent invention. Similar to the joist described above with respect toFIGS. 1 and 2, each joist 1010 a and 1010 b illustrated in FIG. 10 mayinclude an upper chord 1012 a and 1012 b and a lower chord 1015 a and1015 b separated by an open web formed from one or more rod-like members1019 a and 1019 b. At the end of each joist 1010 a and 1010 b, adiagonal end member 1025 a and 1025 b extends from the lower chord 1015a and 1015 b proximate the first web connection to the end of the upperchord 1012 a and 1012 b proximate the joist shoe 1070 a and 1070 b.Shoes 1070 a and 1070 b are attached to the ends of the upper chords1012 a and 1012 b to form an I-beam configuration at the end of eachjoist 1010 a and 1010 b. The bottom surface of each shoe 1070 a and 1070b is supported by the top surface of the beam 1065.

In the illustrated embodiment, the ends of the joists are configuredsuch that they extend less than halfway across the beam 1065, thereby,creating a gap between the ends of the opposing joists. In theillustrated embodiment, the ends of the opposing joists 1010 a and 1010b are seated on the beam 1065 at approximately the same location alongthe beams longitudinal axis. In other embodiments, however, the opposingjoists 1010 a and 1010 b may be staggered along the longitudinal axis ofthe beam 1065.

As further illustrated by FIG. 10, each joist 1010 a and 1010 b supportscorrugated steel decking 1020 a and 1020 b. The corrugated steel decking1020 a and 1020 b is positioned such that the corrugations runperpendicular to the joists 1010 a and 1010 b. The corrugated steeldecking 1020 a and 1020 b is also positioned such that the corrugatedsteel decking 1020 a and 1020 b on either side of the beam 1065 ends ator before the beam 1065. By ending the corrugated steel decking 1020 aand 1020 b at or before the beam 1065, an opening is created above thebeam 1065 that exposes the top of the beam, the ends of the upperchords, and the ends of the joist shoes. When concrete is placed overthe corrugated steel decking to form the concrete slab, concrete ispermitted to flow or is placed into the opening above the beam 1065 tocreate a concrete distribution/collector beam that extends above thesteel beam 1065 and encapsulates the ends of the upper chords and thejoist shoes in the concrete 1040. Z-shaped closures 1050 a and 1050 bare positioned on either side of the beam 1065 to form the walls of achannel that the concrete is placed into and, thus, form the walls ofthe concrete distribution/collector beam.

More specifically, each z-shaped closure has a generally horizontallower flange 1051 a and 1051 b that rests atop the steel beam 1065. Ascrew, weld, powder actuated fastener, pneumatic pin, or a variety ofother fasteners may be used to couple each horizontal lower flange tothe steel beam 1065. The generally horizontal upper flanges 1053 a and1053 b of the z-shaped closures extend away from the beam 1065 and atleast a portion of each horizontal upper flange 1053 a and 1053 b restsatop a peak in the corrugated steel decking 1020 a and 1020 b. A screw1058 may be used to couple each horizontal upper flange 1053 a and 1053b to a respective peak in the corrugated steel decking 1020 a and 1020b. Each z-shaped closure 1050 a and 1050 b further includes a verticalface 1052 a and 1052 b extending between the upper and lower flanges toform the vertical walls of the channel. As described above with respectto FIG. 3, the vertical faces 1052 a and 1052 b have cutouts that allowthe closures 1050 a and 1050 b to fit around the contours of the I-beamcreated by the ends of the upper chords and the joist seats.

As described above with respect to the FIGS. 1 and 2, self-drilling,self-tapping stand-off screws 1030 a and 1030 b are positioned throughthe corrugated steel decking and the upper chords of the joist in atleast some of the valleys of the corrugated steel decking. In someembodiments, self-drilling, self-tapping stand-off screws 1031 a and1031 b are also positioned in the flanges of the upper chords 1012 a and1012 b proximate the ends of the upper chords in the region above thesteel beam 1065.

FIG. 11 illustrates a sectional side view of a composite joist floorsystem 1100 showing where the corrugated steel decking 1120 is supportedat its edge by a wall 1160 that runs substantially parallel to thejoists 1110. The wall 1160 may be, for example, comprised of a pluralityof steel studs. A cold-formed wall track 1162 may be positioned over theends of the studs and may run along the top of the wall to distributeforces from the composite joist floor to the load bearing wall studs. Aself-tapping screw 1161 may be drilled through a valley in thecorrugated decking 1120 and into the cold-formed wall track 1162 tocouple the edge of the concrete floor slab 1140 to the wall 1160. Insome embodiments, the self-tapping screw 1161 may be a self-tapping,self-drilling stand-off screw, such as the one's described above withrespect to FIG. 4.

As further illustrated in FIG. 11, the corrugated steel decking 1120may, in some embodiments, only extend over a portion of the supportingwall 1160 so that the un-cured concrete 1140 can flow or be placed overthe edge of the corrugated steel decking 1120 and onto the top of thecold-formed wall track 1162. If the floor is to end at the edge of thewall 1160, a pour stop 1155, such as the pour stop described above withrespect to FIGS. 1 and 2, may be used to contain the un-cured concrete1140 during concrete placement and curing.

As further illustrated, one or more self-drilling, self-tappingstand-off screws 1131 may be drilled through the cold-formed wall track1162 in the region over the wall 1160 beyond the edge of the corrugatedsteel decking 1120. As will be described in greater detail below, usingself-drilling, self-tapping stand-off screws 1131 in this manner at thetops of the walls or other supporting members can provide significantstructural advantages. For example, in some embodiments, the cold-formedwall track 1162 is a cold-formed steel section that rests atop aplurality of the cold-formed steel wall studs. The stand-off screws 1131installed along the top of the wall in the cold-formed steel wall track1162 transfer forces between the cold-formed steel wall track 1162 andthe concrete 1140 allowing the two structures to act more like a singleunit. As such, the structure may be significantly stronger and/ormaterial may be reduced in the cold-formed wall track 1162 used in thefloor system. Furthermore, as will also be described in greater detailbelow, stand-off screws 1131 installed at the tops of shear walls mayalso have significant structural advantages with regard to transferringhorizontal diaphragm forces from the floor to the shear wall.

In FIG. 11, the wall 1160 is the proper height to directly support theedge of the corrugated steel decking 1120. In other embodiments,however, z-shaped closures may be used at the inside edge of the wall tosupport the corrugated steel decking 1120. In this way, a largerconcrete distribution/collector beam can be created over the top of thewall that can provide various structural advantages and improve thestructures fire safety rating. For example, FIG. 12 illustrates across-sectional view of a composite joist floor system 1200 where anexternal masonry wall 1260 that is substantially parallel to the floorjoist 1210 supports the edge of the corrugated steel decking 1220 usinga z-shaped closures 1250 to support the edge of the corrugated steeldecking 1220, in accordance with an embodiment of the present invention.

More particularly, the z-shaped closure 1250 comprises a generallyhorizontal lower flange 1251 that is coupled to the top of the wall 1260by, for example, a masonry screw 1257. The z-shaped closure 1250 furthercomprises a generally horizontal upper flange 1253 that abuts andsupports the lower side of the edge of the corrugated steel decking1220. Self-tapping screws 1258 may be used to couple the valleys in thecorrugated steel decking to the upper flanges of the z-shaped closure1250. A vertical face 1252 extends between the upper and lower flanges1253, 1251 and forms the walls of the concrete beam 1241.

Since the wall 1260 is an external wall, a pour stop 1255 is used toform the exterior wall of the concrete slab 1240 and beam 1241. The pourstop 1255 comprises a generally horizontal lower flange 1271 and agenerally vertical face 1272. The generally horizontal lower flange 1271may be coupled to the top of the wall 1260 by, for example, a masonryscrew 1257. It should be appreciated that the length of the verticalfaces of the pour stop 1255 and the z-shaped closure 1250 determine thesize of the concrete distribution/collector beam 1241 over the wall 1260and the distance that this beam 1241 extends below the bottom of thedecking 1220. Therefore, the pour stops 1255 and z-shaped closures 1250can be varied to change the structural characteristics of the floorsystem depending on the design requirements. The pour stops 1255 andz-shaped closures 1250 can also be used to alter the noise attenuatingand fire containing properties of the structure. Furthermore, when thesupporting structure is a masonry wall such as in FIG. 12a , the heightof the pour stop 1255 and z-shaped closure 1250 can be selected so thatthe height of the resulting concrete beam 1241 matches the masonrycourse height or some desired multiple thereof.

FIG. 12b illustrates an interior demising wall 1260 b that is parallelto the floor joists 1210 a, 1210 b. Since the demising wall 1260 bsupports corrugated decking 1220 a and 1220 b on each side of the wall1260 b, two z-shaped closures 1250 a and 1250 b are used to support thedecking 1220 a and 1220 b, respectively, and to create the walls of thechannel that forms the concrete distribution/collector beam 1241 b abovethe wall 1260 b. Typically fire caulking is required at the top of ademising wall or some other fire stop must be installed in thecorrugations of the metal decking 1220 a and 1220 b between the deckingand demising wall in order to meet the proper fire safety designrequirements. However, the z-shaped closures 1250 a and 1250 b may beused to create a concrete beam 1241 b that is large enough and createsenough of a fire barrier so that additional fire proofing may not berequired at the juncture between the floor and the demising wall. Thiscan save significant time and cost during construction of the structure.

Flush Seat Configuration for Composite Joist Floor System

FIG. 13 illustrates a sectional side view of a composite joist floorsystem 1300 where the joist 1310 is supported by a wall 1360 runningperpendicular to the joist 1310 in accordance with another embodiment ofthe present invention. The configuration of the joist 1310 and the joistshoe 1370 are generally similar to the joists and joist shoes describedabove, however, the composite joist floor system 1300 uses a “flushseat” configuration to support the end of the joist 1310.

Referring to FIG. 13, in the flush seat configuration the top of theupper chord 1312 is secured such that it is substantially flush with thetop of the supporting member, such as the supporting wall or, in thiscase, a distribution member 1365 or header positioned at the top of asupporting wall 1360. The flush seat configuration includes a generallyhorizontal plate 1375 that is welded to the top surface of the end ofthe upper chord 1312. The horizontal plate 1375 extends beyond the endof the upper chord 1312 so that a portion of the plate 1375 rests uponthe top surface of the distribution member 1365. In the illustratedembodiment, a substantially vertical plate 1377 extends downward fromthe horizontal plate 1375 at a location on the horizontal plate 1375just beyond the end of the upper chord 1312. The vertical plate 1377extends downward just below the lower surface of the joist shoe 1370.The joist shoe 1370 is welded to the joist such that it extends slightly(e.g., ¼ of an inch) beyond the end of the upper chord 1312. This slightextension of the joist shoe 1370 allows the vertical plate 1377 to bewelded the horizontal plate 1375 without interfering with the end of thejoist's upper chord 1312. The welding of the vertical plate 1377 to thebottom of the joist shoe 1370 applies the vertical load into the bottomof the joist shoe 1370 and minimizes eccentricity on the joist end.

In the flush seat configuration illustrated in FIG. 13, the corrugatedsteel decking 1320 extends over the horizontal plate 1375 and ends afterit extends approximately half way (or, for example, at least 2.5 inches)across the supporting wall 1360. As also illustrated, in a preferredembodiment, the self-drilling, self-tapping stand-off screws 1320installed into the joist's upper chord 1312 proximate to the flush seatconfiguration are preferably positioned closer to each other than thetypical spacing of the self-drilling, self-tapping stand-off screwsalong the joist 1310.

FIG. 14 illustrates another embodiment of a flush seat configurationwhere two opposing joists 1410 a and 1410 b are supported by the samesteel beam 1460. In the illustrated composite joist floor system 1400,the horizontal plates 1475 a and 1475 b, the vertical plates 1477 a and1477 b, and the joist shoes 1470 a and 1470 b are each configuredsimilar to the corresponding plates and shoes described above withreference to FIG. 13. In FIG. 14, however, the corrugated steel decking1420 extends from the first joist 1410 a completely over the beam 1460to the second joist 1410 b.

FIG. 15 illustrates a flush shoe configuration 1500 where the flushbearing seat 1574 is configured specifically for a masonry-type supportmember, such as a block wall, in accordance with an embodiment of thepresent invention. Specifically, the portion of the horizontal plate1575 extending beyond the vertical plate 1577 is bent downward. In thisway, the horizontal plate 1575 is pre-bent to concentrate the downwardforce more toward the center of the concrete channel 1565 rather thantoward the top inside corner of the top block in the masonry wall 1560.

Diaphragm Attachment Using Stand-Off Screws

FIGS. 16a and 16b illustrate a top view and a side section view,respectively, of a composite floor system 2700 in accordance with anembodiment of the present invention. Specifically, FIGS. 16a and 16billustrate how the composite floor system 2700 may be configured totransfer horizontal diaphragm shear forces 2705 from the concrete slab2740 to the primary support structures, such as a cold-formed steelshear-wall 2760, in accordance with an embodiment of the presentinvention. In addition to transferring horizontal diaphragm loads fromthe slab to the wall, the techniques described herein also provide forthe transfer of other forces between the two structures. For example,the force exerted by wind blowing against the an exterior wall can betransferred from the wall to the concrete slab more efficiently usingthe systems described herein. The corrugated decking 2720 and theconcrete slab 2740 are not shown in FIG. 16a for clarity.

As illustrated in FIGS. 16a and 16b , in addition to the frictionbetween the concrete slab 2740 and the top of the wall 2760, embodimentsof the present invention use two primary techniques for transferringdiaphragm shear forces from the concrete slab 2740 to the shear wall2760. In some embodiments of the present invention both techniques areused together, while in other embodiments of the present invention oneor none of the techniques may be used. In the first technique, the joistshoes 2770 are attached to the top of the wall 2760 by, for example,self-drilling screws 2780 or other fasteners. By securing the ends ofthe joists 2710 to the top of the wall 2760 and by using theself-drilling stand-off screws 2730 to couple the joist to the concreteslab as described above, the shear forces are transferred from the slab2740 into the joist 2710 by the stand-off screws 2730 and then from thejoist 2710 into the wall 2760 by the self-drilling screw 2780 or otherfastener used to attach the joist 2710 to the wall 2760.

As illustrated in FIG. 16b , in one embodiment of the floor system, thejoist shoes 2770 extend over the supporting wall 2760 beyond the end ofthe joist's upper chord 2712 so that there is sufficient room for theself-drilling screws to be drilled through the joist shoe 2770 and intothe top of the wall 2760 and/or distribution plate 2762. In someembodiments, self-tapping, self-drilling stand-off screws are used tofasten the joist shoes 2770 to the wall 2760.

In the second technique for transferring horizontal diaphragm forcesfrom the concrete slab 2740 to the shear wall 2760, self-drillingstand-off screws 2785, which may be the same size as or a different sizefrom the stand-off screws 2730 installed in the decking 2720 and joists2710, are installed into the top of the wall 2760 (or distribution plate2762, member, wall track, or header, as the case may be) at designspacing. These stand-off screws 2785 then function to transfer thediaphragm shear forces from the concrete 2740 to the wall 2760. Asdescribed above, in preferred embodiments, the stand-off screws 2785 areheat treated in such a way that the lower portion of the screw has agreater hardness than the upper shank portion of the screw.

FIG. 16a illustrates an exemplary embodiment of the invention where asingle row of stand-off screws 2785 are installed into the top of wall2760. In other embodiments, more than one row of stand-off screws 2785may be installed into the top of the wall 2760. Where more than one rowof stand-off screws 2785 are used, the rows may be aligned and have thesame screw spacing such that each stand-off screw 2785 is installed nextto a corresponding stand-off screw in the other row(s). In otherembodiments, the rows may be configured such that they are not alignedand/or have different screw spacings such that the stand-off screws 2785are staggered relative to the stand-off screws 2785 in the other row(s).

FIG. 17 illustrates a side section view of a portion of the floor system2700 at an external wall that is substantially parallel to the floorjoists 2710, in accordance with an embodiment of the present invention.As illustrated in FIG. 17, two rows of stand-off screws 2785 areinstalled into the top of the wall 2760 to transfer horizontal diaphragmforces from the concrete slab 2740 to the external wall 2760. Asdescribed above, although two side-by-side rows of stand-off screws 2785are illustrated in the FIG. 17, in other embodiments any number of rowsmay be used and the rows may be staggered relative to each other.

Although FIGS. 16 and 17 illustrate external walls, the stand-off screwscan also be used in a similar manner to transfer diaphragm forces fromthe concrete slab 2740 to interior walls or support beams, as the casemay be. In this regard, FIG. 18 illustrates an interior support wall2761 in which stand-off screws 2785 have been installed into the top ofthe wall 2761 to transfer diaphragm forces from the concrete slab 2740to the wall in accordance with an embodiment of the present invention.

Furthermore, although the figures illustrate installation of thestand-off screws 2785 into cold-formed steel wall studs and steeldistribution plates or wall tracks, the stand-off screws may besimilarly used in support structures made of other materials. Forexample, stand-off screws may be used at the tops of masonry walls orwood-framed walls. In such embodiments, the stand-off screws arepreferably modified such that the stand-off screws have threads andhardnesses that are tailored to meet the requirements of the materialbeing driven into. Exemplary stand-off screws specifically configuredfor installation into wood or masonry support structures are describedin greater detail below.

Composite Wood Joist Floor System

FIG. 19 illustrates a composite joist floor system 2100 where the joists2110 are made of wood in accordance with an embodiment of the presentinvention. As illustrated, the wood joists may comprise solid wood beams2110 b or wood trusses or I-beams 2110 a. In the case of wood trusses orI-beams 2110 a, the chords and the webs (which may be open webs orclosed webs) may both be made of wood or, in other embodiments, thechords may be made of wood and the webs may comprise another materialsuch as a metallic material. The wood joists 2110 are covered by aforming material 2120, which may be wood flooring, light gauge metaldecking, or some other material. The stand-off wood screws 2130 are theninstalled through the flooring 2120 and into the joists 2110. In oneembodiment, the forming material 2120 is pre-punched so that thestand-off wood screws 2130 can be installed therethrough without havingto drill through the forming material 2120. Whether the forming material2120 is pre-punched or not, the clamping collar 2126 on the stand-offwood screw 2130 draws the flooring 2120 tight against the wooden floorjoist. A cementitious floor topping is placed over the forming material2120 and encapsulates the stand-off shank portion of the stand-off woodscrew 2130. As described above with respect to other embodiments of thepresent invention, the stand-off screws 2130 result in a stiffer andstronger wooden floor system by causing the cementitious floor toppingto effectively function as an upper chord of the wood floor joists.

FIG. 20 illustrates a side view of a stand-off wood screw 2130illustrated in FIG. 19, in accordance with an embodiment of the presentinvention. Each stand-off wood screw 2130 has an elongated shank 2217with an unthreaded shank portion 2219 and integral threaded screwportion 2218 having helical threads. The threaded screw portion 2218 isconfigured to have a wood screw thread pattern. As illustrated in FIG.19, the threaded screw portion 2218 may vary in length depending on thesize and type of wood joist 2110 a, 2110 b used in the flooring system2130.

The unthreaded shank portion 2219 may also vary in height depending onthe thickness of the cementitious topping 2140 that is planned for thefloor system 2100. For example, the unthreaded shank portion 2219 maytypically range from about one (1) inch to about four-and-a-half (4.5)inches in length depending on the application and the thickness of thecementitious material. Located at the end of the stand-off wood screw2130 opposite the drill tip 2222 is a driving head 2221 configured toengage a driving tool capable of rotating the stand-off wood screw 2130.In one embodiment, the driving head 2221 comprises a hexagonal headconfigured to mate with a hexagonal socket. An integral angular flangeor clamping collar 2226 is located between the threaded and unthreadedportions 2218 and 2219 of the stand-off screw 2130. As described abovewith reference to FIG. 19, this clamping collar 2226 functions to drawthe forming material 2120 down against the wood joist 2110. In oneembodiment, a portion of the stand-off wood screw 2130 is unthreaded2216 below the clamping collar 2226 between the clamping collar 2226 andthe threaded screw portion 2218.

The stand-off wood screw is generally relatively ductile so that thescrew may bend slightly with movement of the cementitious toppingmaterial and not break under the shear loads that the stand-off screw2130 will likely experience under load. Furthermore, the fact that thestand-off screws are at least somewhat ductile allows a stand-off screw2130 to share the shear loads in cementitious material with neighboringstand-off screws.

In other embodiments of the stand-off wood screw 2130, however, thescrew may have a uniform hardness since the hardness required to drillinto the wood floor may be soft enough to prevent the screw frombreaking under the shear loads presented by the cementitious flooringlayer 2140.

Stand-off wood screws 2130 of the type illustrated in FIG. 20 are notlimited to use with wood joists and may also be used in conjunction withother wood structural members. For example, where wood distributionmembers or headers are used at the top of a support wall and where theconcrete or cementitious material contacts the top of the wall, thestand-off wood screws 2130 can be installed into the wood distributionmember or header to form a composite distribution member or headerand/or to transfer diaphragm forces from the cementitious material tothe wall.

Composite Cold-Formed Steel Joist Floor System

In some embodiments of the present invention, various different types ofcold-formed steel floor joists are used in addition to or as analternative to open web steel joists. For example, FIG. 21 illustratesthree different exemplary cold-formed steel floor joists 2310 a, 2310 b,and 2310 c. In each of these examples, self drilling, self-tappingstand-off screws 2330 are installed through the corrugated steel decking2320 and into the cold formed steel floor joist 2310 and function topull the decking 2320 against the joists 2310. The stand-off portion ofthe screws 2330 are then encapsulated in the concrete slab 2340providing a composite structure that increases the stiffness and loadcarrying capacity of the floor.

Cold-Formed Steel Composite Header

In some embodiments of the present invention, one or more headers areused at the tops of supporting walls and/or over, doors, windows, orother openings in the walls. In conventional floor systems designed forheavy loads, the connections between the header and the jambs at eitherside of the opening are often some of the most expensive connectionswithin the wall system since the load of the floor above the openingmust be properly distributed to wall structures on either side of theopening. Embodiments of the present invention provide a floor systemthat has a composite header design that may reduce the cost of theseconnections.

FIGS. 22a and 22b illustrate a composite floor system 2400 having acomposite header configuration in accordance with and embodiment of thepresent invention. In the illustrated embodiment, the header 2480 is acold-formed steel header comprised of a plurality of cold-formed steelsections. Specifically, the header 2480 is comprised of two opposingC-sections 2464 and two opposing tracks 2462. As illustrated in FIG. 22b, the header 2480 generally spans an opening 2405 in the wall 2460. Theheader is generally supported on each end by a jamb 2406. As describedabove, z-shaped closures 2450 and pour stops 2455 can be used to definea channel over the top of the wall 2460. Concrete 2440 can be placed inthis channel and cured to form a concrete distribution/collector beam2441 on the top of the wall 2460 and extending over the header 2480. Asillustrated in FIGS. 22a and 22b , one or more self-drilling,self-tapping stand-off screws 2485 may be installed into the header 2480prior to the concrete placement. These stand-off screws 2485 may be ofthe same type and size as the stand-off screws 2430 installed into theupper chords of the joist 2410 or they may be of a different size and/ortype as required by the design parameters.

When the concrete 2440 is placed over the wall 2460 and allowed to cure,the upper stand-off portions of the screws 2485 become encapsulatedwithin the concrete beam 2441. In this way, a composite header is formedand loads in the cold-formed steel header 2480 may be transferred intothe concrete beam 2441 and vice versa such that the concrete beam andthe cold-formed steel header 2480 function as a single unit. By lockingthe concrete to the header via composite action, the cold-formed steelheader 2480 may be constructed of a lighter gauge material. Conversely,the composite header can safely support increased vertical loads withreduced deflection compared to a normal non-composite header. Thecomposite header may also reduce costly header-to-jamb connections forheavy loads by distributing much of the shear at the ends of the headerinto the jambs through the concrete. With the composite header, some ofthe vertical load will be transferred through the concrete slab into thejambs. This contrasts with a normal header where all of the verticalload must be transferred out of the header via direct connectionsbetween the header and the jambs. As further illustrated in FIG. 22a ,in some embodiments of the invention the self-drilling, self-tappingstand-off screws 2485 also function to attach the z-shaped closure 2450and the pour stop 2455 to the cold-formed steel header 2480.

FIG. 22a also illustrates how, in some embodiments, the joist seat orshoe 2470 may be spaced apart from the joist's upper chord 2412 andconnected by the end diagonal 2425 and/or other connecting members 2426.Such a configuration in combination with appropriately sized z-shapedclosures 2450 and pour stops 2455 allow for variations in the height ofthe concrete distribution/collector beam 2441 that is formed above thewall 2460.

Improved Stand-Off Screw and Composite Floor System for TransferringForces Between the Concrete Slab and the Support Structures

FIG. 23 illustrates a composite floor and wall system 2500 in accordancewith another embodiment of the present invention. As described above, aconcrete floor system may comprises rebar 2545 embedded within theconcrete 2540 to reinforce the concrete slab 2540. In general, the rebaris spaced both perpendicular and parallel to the walls. In someembodiments, the perpendicular and parallel rebar members are welded orotherwise coupled together at their intersections to form a welded wirefabric. These welds may be made before or after positioning the rebarover the corrugated decking 2520 in the floor system. In otherembodiments, the rebar may be positioned in other formations in theconcrete slab based on the particular design requirements.

FIG. 23 illustrates an embodiment of the present invention where rebar2545 in the concrete slab 2540 is coupled to a stand-off screw 2585installed into the top of a supporting wall 2560. Specifically, FIG. 23illustrates the top of a masonry wall 2560. The masonry wall 2560 maycomprise a concrete-filled channel 2565 running through the uppermostblocks or bricks in the wall 2560 so that masonry screws may be insertedinto the concrete and so that forces from the floor may be more evenlydistributed throughout the wall 2560. As also illustrated in FIG. 23,the concrete-filled channel 2565 may have rebar 2562 provided thereinfor reinforcing the concrete in the channel 2565. In general, whenstandard masonry screws or stand-off screws 2585 having masonry threadsare installed into the concrete, the concrete is pre-drilled to providea hole for the masonry screw or stand-off screw to be threaded into.

As described above, a stand-off screw 2585 may be installed into the topof a supporting wall 2560 and z-closures 2550 and pour stops 2555 may beused to create a concrete distribution/collector beam 2541 at the top ofthe wall that encapsulates the stand-off end of the stand-off screw2585. As also described above, installing the stand-off screws 2585 intothe top of the wall in this manner creates composite action between theconcrete beam 2541 and the wall 2560 or the header, as the case may be.The stand-off screws 2585 also function to transfer horizontal diaphragmforces from the concrete slab 2540 to the shear wall 2560. To improvethe connection between the floor and the wall and to, thereby, improvethe transfer of forces between the floor and the wall and increase thecomposite action so that the walls and the floors function more like asingle unit, embodiments of the present invention couple the end of eachrebar member 2545 that intersects with the wall 2560 to the top of astand-off screw 2585 installed in the top of the wall 2560. In anexemplary embodiment of the present invention, specially-designedstand-off screws are used that allow the rebar to be more easily coupledto the stand-off end of the screw.

For example, FIGS. 23 and 24 illustrate a stand-off screw 2585configured to attach to a rebar member or some other extension member atthe end of the screw opposite the screw's tip 2587, in accordance withan embodiment of the present invention. As illustrated in FIG. 24, thestand-off screw 2585 generally comprises a lower threaded portion 2586and an upper un-threaded shank portion 2588. In the illustratedembodiment, the lower threaded portion 2586 comprises threads configuredfor drilling into concrete or other masonry materials. In otherembodiments, the lower threaded portion 2586 may be configured fordrilling into other materials such as steel or wood. Similar to thestand-off screws described above with respect to FIG. 4, the stand-offscrew 2585 may be specially heat treated so that tip and a lower portionof the screw is harder than the upper portion of the screw.

Similar to other stand-off screws described above, the stand-off screw2585 illustrated in FIGS. 23 and 24 generally has a driving head 2592,such as a hexagonal head, proximate to the end of the screw opposite thetip 2587 and configured to engage a driving tool capable of rotating thestand-off screw 2585. However, unlike the other stand-off screwsdescribed above, this stand-off screw 2585 has an extension couplingportion 2593 located above the driving head 2592 at the extreme end ofthe stand-off screw 2585.

The extension coupling portion 2593 is configured to couple to a rebarmember in the floor system or some other member that will effectivelyextend the length of the stand-off screw 2585. In the embodimentillustrated in FIGS. 23 and 24, the extension coupling portion 2593comprises a threaded portion. As illustrated in FIG. 23, a couple nut2595 having two opposing female connectors may be used to join the endof the stand-off screw 2585 to the end of the rebar member 2545 or otherextension. Where the end of the stand-of screw 2585 is threaded, atleast one of the female connectors in the couple nut 2595 hascorresponding threads so that the couple nut may be screwed on to theend of the stand-off screw 2585. In one embodiment, the end rebar member2545 is also threaded and screws into the second female connector of thecouple nut 2595. In other embodiments, the second female connector ofthe couple nut 2595 is not threaded and is configured to receive andhold the end of the rebar 2545 therein by other means. For example, anadhesive, a fastener, and/or a weld may be used to hold the end of therebar in the end of the couple nut 2595 at least until the concrete 2540cures around the connection.

Of course, the stand-off screw 2585 illustrated in FIG. 24 may also beused without connecting it to a rebar member to perform the functions ofthe stand-off screws described above with respect to other embodimentsof the present invention. For example, FIGS. 25 and 26 illustrateembodiments of the present invention in which the stand-off screw 2585is being used for functions other than or in addition to coupling thewall to a rebar member in the floor.

More particularly, FIG. 25 illustrates a stand-off screw 2585 used toattach a joist shoe 2570 to the supporting wall 2560 in accordance withan embodiment of the present invention. In the illustrated embodiment,the supporting wall 2560 is a masonry wall and the joist shoe 2570 isextended to allow for installation of the stand-off-screw 2585therethrough. In the illustrated embodiment, where the joist shoe 2570is metal and the wall is masonry, the stand-off screw 2585 used in thissystem will generally have threads designed for drilling into masonryand the joist shoe 2570 may be pre-punched or drilled to allow the lowerthreaded portion of the screw 2585 to pass therethrough. Preferably, ifthe joist is pre-punched or pre-drilled, the pre-punched pr pre-drilledhole has a diameter greater than the diameter of the screw's lowerthreaded portion but less than the diameter of the screw's clampingcollar 2590.

FIG. 26 illustrates how the stand-off screws 2585 may also be used toattach a z-shaped closure 2550 and a pour stop 2555 to a wall 2560,while also functioning to couple rebar 2545 to the wall 2560 and/or totransfer horizontal diaphragm forces from the slab 2540 to the wall2560. Where the z-shaped closure 2550 and the pour stop 2555 are metaland the wall 2560 is masonry, the z-shaped closure 2550 and the pourstop 2555 are generally pre-punched to have holes at the required designintervals to allow the threaded portions of the stand-off screws 2585 topass therethrough.

As described above, extension members other than rebar may also becoupled to the ends of the stand-off screws 2585. For example, in anembodiment of the present invention where the concretedistribution/collector beam that is to be formed over a supporting wallis particularly large, the stand-off screws 2585 available may beshorter than what would be ideal for coupling the concretedistribution/collector beam to the wall. In such an embodiment,extensions may be added to the end of the stand-off screw 2585, via acouple nut or via other fastening systems, to increase the length of thestand-off screw 2585 and/or to change the shape of the end of thestand-off screw 2585.

Therefore, it should be appreciated that the improved stand-off screw2585 illustrated in FIGS. 23-26 permits the efficient transfer ofdiaphragm loads from the concrete floor slab into the supporting walls.This may be particularly advantageous for structures having masonrysupporting walls. The conventional method of joining a masonry wall to aconcrete floor would be to embed rebar into the masonry wall duringconstruction of the wall such that portions of the rebar extend out ofthe top of the masonry wall. In this conventional method, thereinforcing bars present a trip hazard for any one walking on the top ofthe wall during construction of the structure. In contrast to theconventional method, the stand-off screws 2585 can be installed justprior to the placing of the concrete floor slab, thereby reducing thetripping potential. Furthermore, the stand-off screw 2585 installationdoes not require skilled labor and the installation spacing is easilyadjusted to match the design diaphragm shear loads.

Balcony Configuration for Composite Joist Floor System

FIGS. 27a and 27b illustrate a composite joist floor system 1600configured to provide for a balcony 1680 that extends from the structureparallel to the floor joists 1610 a, 1610 b, and 1610 c, in accordancewith an embodiment of the present invention. Specifically, FIG. 27aillustrates a cross-sectional front view of the composite joist floorsystem 1600, including the backspan 1685 used to support thecantilevered balcony 1680. FIG. 27b illustrates a cross-sectional sideview of the composite joist floor system 1600. To sufficiently supportthe balcony 1680, the composite joist backspan 1685 must generally bethicker than the rest of the composite joist floor. Therefore, in orderto maintain a level floor, the corrugated steel decking 1621 must belowered to accommodate the increased concrete thickness in the backspan1685. As such, additional angles 1687 are welded to the sides (e.g., thevertical webs 1611) of the joists 1610 a-c to provide seats for theedges of the corrugated steel decking 1621 below the level of thestandard corrugated steel decking 1620. Since joist 1610 b is a standardjoist, the upper chord 1612 of the joist 1610 b is encapsulated inconcrete within the backspan 1685.

To prevent concrete from pouring out of the gaps between the standardcorrugated steel decking 1620 and the lowered corrugated steel decking1621, a couple of different closures are used. For example, asillustrated in FIG. 27a, z -shaped closures 1650 are positioned suchthat the horizontal lower flange is coupled to the peaks in the lowercorrugated steel decking 1621 and the horizontal upper flange is coupledto the peaks of the standard corrugated steel decking 1620. Angle-shapedclosures 1654 may be used to substantially prevent concrete 1640 fromescaping through the corrugations under the lower flanges of thez-shaped closures 1650 and under the lower corrugated steel decking1621. As illustrated in FIG. 27b, z -shaped closure 1652 is positionedalong the rear of the backspan 1685 such that the horizontal lowerflange extends below at least one valley in the lower corrugated steeldecking 1621 and the horizontal upper flange extends over at least onepeak in the standard corrugated steel decking 1620.

FIGS. 28a and 28b illustrate a composite joist floor system 1700configured to provide for a balcony 1780 that extends from the structureperpendicular to the floor joists 1710 a, 1710 b, and 1710 c, inaccordance with an embodiment of the present invention. Specifically,FIG. 28a illustrates a cross-sectional side view of the composite joistfloor system 1700, including the backspan 1785 used to support thecantilevered balcony 1780. FIG. 28b illustrates a cross-sectional frontview of the composite joist floor system 1700 and specificallyillustrates stepped joist 1710 c. To sufficiently support the balcony1780, the composite joist backspan 1785 must generally be thicker thatthe rest of the composite joist floor. Therefore, in order to maintain alevel floor, the corrugated steel decking 1721 must be lowered relativeto the standard corrugated steel decking 1720 to accommodate theincreased concrete thickness in the backspan 1785. As such, anadditional angle 1787 is welded to the side (e.g., the web) of the joist1710 b to provide a seat for one edge of the corrugated steel decking1721 below the level of the standard corrugated steel decking 1720. Insome embodiments, where the backspan is under a certain size, thelowered corrugated steel decking 1721 may be supported by the angle 1787on one side and the wall 1760 or other supporting member on the other.However, in the illustrated embodiment, a joist 1710 c is required toprovide additional support for the backspan 1785 midway between the wall1760 and the joist 1710 b.

FIG. 28b illustrates joist 1710 c in accordance with an embodiment ofthe present invention. Specifically, joist 1710 c has a step down in itsspan to support the corrugated steel decking 1721 of the backspan. FIGS.28a and 28b also illustrate how z-shaped closures and angle-shapedclosures may be used to prevent concrete from pouring out of the gapsbetween the standard corrugated steel decking 1720 and the loweredcorrugated steel decking 1721. As illustrated in FIG. 28a, z -shapedclosure 1752 is positioned along the rear of the backspan 1785 such thatthe horizontal lower flange is coupled to the peaks in the lowercorrugated steel decking 1721 and the horizontal upper flange is coupledto the peaks of the standard corrugated steel decking 1720. Angle-shapedclosures 1754 may be used to substantially prevent concrete 1740 fromescaping through the corrugations under the lower flange of the z-shapedclosure 1752 and under the lower corrugated steel decking 1721. Asillustrated in FIG. 28b, z -shaped closures 1752 are positioned oneither side of the backspan 1785 such that the horizontal lower flangeseach extend below at least one valley in the lower corrugated steeldecking 1721 and the horizontal upper flanges each extend over at leastone peak in the standard corrugated steel decking 1720.

FIG. 29 illustrates a composite joist floor system 1800 where theconcrete floor ends at a joist 1810 in accordance with an embodiment ofthe present invention. In such a system, the joist 1810 supports one endof the corrugated steel decking 1820 by a portion of a horizontal flangeof the upper chord 1812. The remainder of the upper chord 1812 supportsa bent plate, such as a quarter-inch bent plate, that has asubstantially horizontal portion 1856 that extends outward away from thejoist 1810 and then bends upward at a right angle to form asubstantially vertical portion 1857. The vertical portion 1857 is usedto contain the concrete 1840 when it is placed over the steel decking1820. An angle-shaped closure 1855 may be used over the end of thecorrugated steel decking 1820 to prevent the placed concrete fromescaping through the gaps between the corrugated steel decking 1820 andthe upper chord 1812 of the joist 1810. In one embodiment, one or morehead studs 1831 are welded to the vertical portion 1857 and extendinward from the vertical portion 1857 toward the joist 1810 so that theyare encapsulated by the concrete 1840. Preferably, steel reinforcingbars and/or welded wire fabric 1845 is also encapsulated within theconcrete 1840 to provide additional reinforcement for the concrete.

Corridors and Mechanical Headers for Supporting Heavy Loads

Many structures require one or more corridors in which HVAC, plumbing,and other large and sometimes heavy loads may be routed. For example,the main pipes and ducts in a structure are often hung from the ceilingof such a corridor. FIG. 30 illustrates a composite joist floor system1900 where a joist 1910 interacts with a corridor 1980 runningperpendicular to the joist 1910 in accordance with an embodiment of thepresent invention. As can be seen in FIG. 30, the configuration of thejoist and the steel decking, load bearing wall studs, concrete, andclosures supported by the joist are similar to those described abovewith respect to other embodiments of the invention. A supporting wall1960 or other supporting member will typically be located where thejoist 1910 intercepts the corridor 1980. For example, the end of thejoist 1910 may be supported by the wall studs in the manner describedabove with reference to FIGS. 1 and 2.

In contrast to the other floor systems described above, the floorspanning the corridor 1980 may not require a joist since the corridor isgenerally relatively narrow. As such, the corridor 1980 may comprisecorrugated steel decking spanning the corridor by extending from thesupporting wall 1960 to another supporting wall (not shown) on the otherside of the corridor 1980, the corrugations of the corrugated steeldecking 1982 being substantially perpendicular to the walls. Since theconcrete 1940 located over the corrugated steel decking 1982 in thecorridor is generally thicker than the concrete located over thestandard corrugated steel decking 1920 and since heavy loads are oftenhung from the ceiling in the corridor, the corrugated steel decking 1982used in the corridor 1980 is typically of a stronger design than thestandard corrugated steel decking 1920 used in many other areas of thestructure. For example, in one embodiment, the corrugated steel deckingover the corridor is a 2-inch deep corrugated steel composite floordecking.

In some instances, the vertical loads generated from hanging pipes,ducts, or other mechanical equipment cannot be safely supported byinserting mechanical anchors through the metal deck into the concreteslab. As such, in some embodiments, mechanical headers are used toprovide support for mechanical equipment that cannot be safely hung fromthe floor spanning the top of the corridor. FIG. 31 illustrates acomposite joist floor system 3000 having a corridor 3080 runningperpendicular to the joists 3010 a and 3010 b and having a mechanicalheader 3090, in accordance with an embodiment of the present invention.As illustrated, the mechanical header 3090, which is generally made ofsteel, spans the corridor 3080 and is supported at each end bysupporting walls or beams 3060 a and 3060 b. Typically the mechanicalheaders span a distance that ranges from 6 to 15 feet. In this way, themechanical header 3090 provides support points for the heavy mechanicalitems, such as ducts 3001 and/or pipes 3002, to hang in the corridor3080.

FIG. 32 provides a more detailed illustration of the mechanical header3080 illustrated in FIG. 31, in accordance with an exemplary embodimentof the present invention. As illustrated, the mechanical header 3080 maybe comprised of a first angle 3081 and a second angle 3082. The firstangle 3081 and the second angle 3082 may be oriented relative to eachother so that they combine to approximately form a “U” shape and so thata flange of the first angle 3081 at least partially overlaps a flange ofthe second angle 3082. The two overlapping flanges may then be coupledtogether by, for example, one or more welds, fasteners, adhesives, orother coupling techniques.

A third angle 3085 and a fourth angle 3086 are welded or otherwisecoupled to each end of the U-shaped member formed by the combination ofthe first angle 3081 and the second angle 3082. As illustrated in FIG.31, the third angle 3085 and the fourth angle 3086 rest on top of thesupporting walls or beams 3060 a and 3060 b, respectively, and functionas the seats for the mechanical header 3090. In a preferred embodimentof the mechanical header 3090, the third angle 3085 and the fourth angle3086 on each end of the header 3090 are sufficiently narrow such thatthe flanges that rest on top of the supporting walls or beams 3060 a and3060 b fit between the corrugations of the corridor's decking 3020 c.This may make installation of the mechanical header 3090 easier andallows the decking 3020 c to bear uniformly on the top of the supportingwall or beam 3060 a and 3060 b as opposed to being lifted up to travelover the seats of the mechanical header 3090.

Referring again to FIG. 32, in some embodiments of the invention, themechanical header 3090 has one or more holes 3083 punched or otherwiseformed into the bottom flange of the header 3090 to provide anchorpoints for hanging equipment from the header. In one embodiment, theholes 3083 are pre-punched at a predetermined spacing, such as every sixinches, to allow for flexibility in where items can be hung once themechanical header is installed.

FIG. 31 illustrates how threaded rods 3095 may be inserted through thepre-punched holes 3083 in the header 3090 to suspend various mechanicaland/or HVAC equipment, such as ducts 3001 and/or pipes 3002, in thecorridor 3080, in accordance with an embodiment of the presentinvention. In a preferred embodiment, no specialty connectors or clampsare required to hang the ducts. Instead, one merely inserts a threadedrod 3095 through the pre-punched holes 3083 in the bottom flange of themechanical header 3090 and threads a nut onto the threaded rod 3095above the bottom flange. A lower support plate 3096 or section havingholes punched therethrough may be used to span two threaded rods 3095 toprovide support for pipes, ducts, or other equipment. The two threadedrods 3095 are inserted through the holes in the support plate 3096 andnuts are threaded onto the threaded rods 3095 below the support plate3096. Adjustments in the vertical location of the support plate 3096 canbe made by adjusting the length of the threaded rods 3095 and/or theposition of the nuts on the threaded rods.

Although embodiments of the present invention described herein aregenerally described as providing a floor structure for a building, itwill be apparent to one of ordinary skill in the art than otherembodiments of the present invention can be similarly used to provide aroof or ceiling structure for a building. Likewise, although someembodiments of the present invention are described as providing abalcony structure for a building, other embodiments of the presentinvention can be similarly used to provide an overhang structure for abuilding.

Specific embodiments of the invention are described herein. Manymodifications and other embodiments of the invention set forth hereinwill come to mind to one skilled in the art to which the inventionpertains having the benefit of the teachings presented in the foregoingdescriptions and the associated drawings. Therefore, it is to beunderstood that the invention is not to be limited to the specificembodiments disclosed and that modifications and other embodiments areintended to be included within the scope of the appended claims.Although specific terms are employed herein, they are used in a genericand descriptive sense only and not for purposes of limitation.

What is claimed is:
 1. A building structure comprising: a plurality offloor joists; one or more support structures for supporting theplurality of floor joists, wherein the one or more support structures atleast comprise a wall with a plurality of studs and an upper wallmember; decking operatively coupled to the plurality of floor joists; aplurality of decking stand-off fasteners operatively coupling thedecking to the plurality of floor joists; a plurality of supportstand-off fasteners extending from the one or more support structures,wherein the plurality of support stand-off fasteners at least extendfrom the upper wall member of the wall with the plurality of studs;wherein a cementitious slab is formed over the decking operativelycoupled to the plurality of floor joists and over at least one of theone or more support structures; wherein the cementitious slabencapsulates at least a portion of the plurality of decking stand-offfasteners and the plurality of support stand-off fasteners; and whereinthe plurality of decking stand-off fasteners and the plurality ofsupport stand-off fasteners help transfer forces between thecementitious slab, the decking, the plurality of floor joists, and theone or more support structures.
 2. The building structure of claim 1,further comprising a closure positioned at a top of the wall to form achannel for the cementitious slab over the wall.
 3. The buildingstructure of claim 2, wherein one or more of the plurality of supportstand-off fasteners operatively couple the closure to the top of thewall.
 4. The building structure of claim 1, wherein one or more of theplurality of support stand-off fasteners operatively couple one or moreof the plurality of floor joists to the one or more support structures.5. The building structure of claim 1, wherein the plurality of floorjoists each comprise: an upper chord; a lower cord: a web operativelycoupled to the upper chord and the lower chord; and a joist shoe on atleast one end of the floor joist; and wherein the joist shoe is locatedbetween the upper chord and the lower chord and is operatively coupledto one of the one or more support structures.
 6. The building structureof claim 5, wherein the joist shoe is spaced apart from the upper chordand the lower chord.
 7. The building structure of claim 5, wherein thejoist shoe extends beyond at least a portion of the upper chord toprovide sufficient room for utilizing a tool to operatively couple thejoist shoe to the one of the one or more support structures.
 8. Thebuilding structure of claim 5, further comprising: a closure positionedat a top of one of the one or more support structures to form a channelfor the cementitious slab over the top of the one of the one or moresupport structures; and rebar located within the channel.
 9. Thebuilding structure of claim 8, wherein the rebar is located below oradjacent to the upper chord.
 10. The building structure of claim 1,wherein the plurality of decking stand-off fasteners and the pluralityof support stand-off fasteners are configured for transferringhorizontal diaphragm forces.
 11. The building structure of claim 1,wherein the plurality of decking stand-off fasteners and the pluralityof support stand-off fasteners comprise a lower stand-off portion and anupper stand-off portion, wherein the upper stand-off portion isconfigured for encapsulation in the cementitious slab.
 12. The buildingstructure of claim 11, wherein the lower stand-off portion of theplurality of decking stand-off fasteners and the plurality of supportstand-off fasteners have a greater hardness than that of the upperstand-off portion of the plurality of decking stand-off fasteners andthe plurality of support stand-off fastener.
 13. The building structureof claim 11, wherein the upper stand-off portion of the plurality ofdecking stand-off fasteners and the plurality of support stand-offfasteners are more ductile than the lower stand-off portion of theplurality of decking stand-off fasteners and the plurality of supportstand-off fasteners.
 14. The building structure of claim 1, wherein eachof the stand-off fasteners comprises a lower screw portion and an upperstand-off portion, wherein the lower screw portion of the deckingstand-off fasteners is screwed through the decking and into theplurality of floor joist, the lower screw portion of the supportstand-off fasteners is screwed into the one or more support structures,and wherein the upper stand-off portion of the decking stand-offfasteners extends from the decking and the plurality of floor joists andis encapsulated within the cementitious slab located above the deckingand the plurality of floor joists, and the upper stand-off portion ofthe support stand-off fasteners extends from the one or more supportstructures and is encapsulated within the cementitious slab locatedabove both the one or more support structures.
 15. The buildingstructure of claim 14, wherein the lower screw portion comprises aself-tapping tip for drilling into the metallic structure.
 16. Thebuilding structure of claim 1, further comprising: a welded wire fabricencapsulated within the cementitious slab.
 17. A building structurecomprising: a plurality of floor joists, wherein the plurality of floorjoists each comprise: an upper chord; a lower cord: a web operativelycoupled to the upper chord and the lower chord; and a joist shoe on atleast one end of the floor joist; and wherein the joist shoe is locatedbetween the upper chord and the lower chord, is spaced apart from theupper chord and the lower chord, and is operatively coupled to one ofthe one or more support structures; one or more support structures forsupporting the plurality of floor joists; decking operatively coupled tothe plurality of floor joists; a plurality of decking stand-offfasteners operatively coupling the decking to the plurality of floorjoists; a plurality of support stand-off fasteners extending from theone or more support structures; wherein a cementitious slab is formedover the decking operatively coupled to the plurality of floor joistsand over at least one of the one or more support structures; wherein thecementitious slab encapsulates at least a portion of the plurality ofdecking stand-off fasteners and the plurality of support stand-offfasteners; and wherein the plurality of decking stand-off fasteners andthe plurality of support stand-off fasteners help transfer forcesbetween the cementitious slab, the decking, the plurality of floorjoists, and the one or more support structures.
 18. The buildingstructure of claim 17, further comprising: a closure positioned at a topof the wall to form a channel for the cementitious slab over the wall;and wherein one or more of the plurality of support stand-off fastenersoperatively couple the closure to the top of the wall.
 19. The buildingstructure of claim 17, wherein the plurality of decking stand-offfasteners and the plurality of support stand-off fasteners areconfigured for transferring horizontal diaphragm forces.
 20. Thebuilding structure of claim 17, wherein each of the stand-off fastenerscomprises a lower screw portion and an upper stand-off portion, whereinthe lower screw portion of the decking stand-off fasteners is screwedthrough the decking and into the plurality of floor joist, the lowerscrew portion of the support stand-off fasteners is screwed into the oneor more support structures, and wherein the upper stand-off portion ofthe decking stand-off fasteners extends from the decking and theplurality of floor joists and is encapsulated within the cementitiousslab located above the decking and the plurality of floor joists, andthe upper stand-off portion of the support stand-off fasteners extendsfrom the one or more support structures and is encapsulated within thecementitious slab located above both the one or more support structures.